The present invention relates to a storage system control method, a storage system, and a storage apparatus.
Recently, there has seen developed a technique called “remote copy”. The remote copy is used to continuously conduct jobs by a computer system in a remote site even when a computer system in a main site stops at occurrence of a disaster caused by, for example, a strong earthquake. The remote copy is a technique to store in a storage volume of a storage apparatus in the remote site a copy or replica of data stored in a storage volume of a storage apparatus in the main site.
On the other hand, to efficiently use a large capacity of storage resources of a storage apparatus, there has been commonly used a configuration to share the storage apparatus among a plurality of information processors. In this case, to guarantee security of data stored in the shared storage apparatus, a technique called “logical unit number (LUN) masking” is employed to beforehand allocate storage volumes to respective information processors. Generally, to identify in a storage apparatus each storage volume thereof, it is possible to use a global identifier uniquely assigned to the storage volume. However, when the LUN masking is used, the identifiers assigned to the storage volumes of each information processor may become discontinuous numbers in some cases. Therefore, in a storage apparatus using the LUN masking, logical identifiers are assigned to storage volumes for each information processor. As a result, when a data input/output request is issued to a storage apparatus, each information processor can identify the storage volume using the local identifier assigned thereto.
In this situation, to use the remote copy, the storage apparatus installed in the main site sends a data input/output request to the storage apparatus installed in the remote site. In the prior art, there does not exit a technique for the storage apparatus in the main site to acquire an identifier locally assigned thereto to identify the storage volume in the remote site. Therefore, the storage apparatus in the main site sends a data input/output request to the storage apparatus in the remote site using a global identifier,
On the other hand, the number of storage volumes is increasing in one storage apparatus. For example, a large-sized storage apparatus includes thousands of storage volumes. Therefore, many bits are required to describe a global identifier in a data input/output request to be sent to the storage apparatus installed in the remote site. However, such a large number of bits are not available for the data input/output request standardized, for example, by the small computer systems interface (SCSI). Therefore, in the remote copy of the prior art, a remote copy command unique to the maker or producer of the storage apparatus is used for each unit or machine type of the storage apparatus.
As above, a remote copy unique to each machine type is conducted in the prior art. It has not been taken into consideration that the remote copy is conducted between storage apparatuses of mutually different unit types and between storage apparatuses of mutually different producers.